Chert (varieties include Jasper or Flint)
Chert (Microcrystalline Silica, formula: SiO2)
sedimentary
Category
Organic Gemstone (Often Associated With Sedimentary Sequences)
Browse organic gemstone (often associated with sedimentary sequences) specimens identified by the Rock Identifier community.
Chert (White-Grey variety)
Microcrystalline or cryptocrystalline Quartz (SiO2)
sedimentary
Chert (Brecciated River Cobble)
Silicon Dioxide (SiO2)
sedimentary
Banded Chert (River Stone/Cobble)
Microcrystalline Quartz (SiO2)
sedimentary
Chert (and Petrified Wood)
Silicon Dioxide (SiO2)
sedimentary
Chert (often called Flint when dark)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Bismuth
Bismuth (Bi)
mineral
Scoria (Vesicular Basalt)
Scoria (Extrusive Mafic Igneous Rock)
igneous
Aventurine (Green Aventurine)
Quartz with Fuchsite Inclusions (SiO2)
Mineral
Carnelian
Silicon dioxide (SiO2) with Iron Oxide impurities (Fe2O3)
mineral
Greenstone
Protolith of basalt, diabase, or gabbro; often contains minerals like chlorite, actinolite, and epidote
metamorphic
Amber
Succinite (specifically for Baltic Amber), Formula: C10H16O
Mineraloid
Red Jasper (Opaque Chalcedony)
Silicon Dioxide (SiO2) with Hematite (Fe2O3) inclusions
mineral
Yellow Chalcedony (Agate/Jasper mix)
Silicon Dioxide (SiO2)
mineral
Diorite
Diorite (intermediate intrusive igneous rock)
igneous
Petrified Wood
Silicified Wood (SiO2)
metamorphic
Halite (Rock Salt)
Halite; NaCl (Sodium Chloride)
Mineral
Gneiss (likely)
Gneiss
Metamorphic
Unakite
Epidote-Feldspar rock (specifically, a variety of granite)
Metamorphic rock
Rhodonite
Rhodonite (MnSiO3)
Mineral
Mixed collection of Quartz varieties, Chalcedony, and metamorphic pebbles
Mixed gemstones (primarily Silicon Dioxide - SiO2)
mineral
Chert (Jasper variety)
Microcrystalline Quartz (SiO2)
sedimentary
Chert / Jasper
Microcrystalline Quartz (SiO2)
sedimentary
Chert (with Quartz Vein)
Chert (Siliceous sedimentary rock, predominantly Microcrystalline Quartz SiO2)
sedimentary
Chert / Flint
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Chert (and/or Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Fossiliferous Limestone (Coquina)
Biogenic Limestone (Calcium Carbonate, CaCO3)
sedimentary
Chert (Flint)
Silicon Dioxide (SiO2)
sedimentary
Quartz (specifically Milky Quartz/Quartzite)
Silicon Dioxide (SiO2)
Mineral
Chalcedony (Agate)
Silicon Dioxide (SiO2)
mineral
Fossiliferous Limestone
Biogenic Limestone (Calcium Carbonate, CaCO3)
sedimentary
Jade (likely Jadeite)
Jadeite (a pyroxene mineral) or Nephrite (a variety of amphibole mineral)
Mineral
Pearl (Cultured or Natural)
Aragonite (CaCO3) with Conchiolin
Organic Mineraloid
Pearl
Calcium Carbonate (CaCO3) in the form of orthorhombic Aragonite and Conchiolin
mineral
Carnelian
Carnelian (SiO2 - Silicon Dioxide with Iron Oxide impurities)
mineral
Purple Agate (Dyed Chalcedony)
SiO2 (Silicon Dioxide) with organic dyes
mineral
Schist
Schist
metamorphic
Quartz (likely Rose Quartz or Milky Quartz based on color)
Quartz (SiO2 - Silicon Dioxide)
Mineral
Porphyritic Rhyolite (Red Porp)
Porphyritic Rhyolite (Felsic volcanic rock)
igneous
Granite
Granite (a plutonic igneous rock composed of quartz, feldspar, and mica)
igneous
Amethyst
Silicon Dioxide (SiO2) containing iron impurities
mineral
Tree Agate
Silicon Dioxide (SiO2) with Dendritic Inclusions
Mineral